It is possible that the main title of the report Marfan Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
As Jenny points out, being able to lisp the alphabet song at age two has little to do with 'knowing' the alphabet. And, yes, most children learn the letters by sight and sound in kindergarten, although most are capable of learning this information sooner if diligently taught by parents or others.
How Babies Learn Language. Every infant is a natural-born linguist capable of mastering any of the world's 7,000 languages like a native. An infant child possesses an amazing, and fleeting, gift: the ability to master a language quickly. At six months, the child can learn the sounds that make up English words and, if also exposed to Quechua and Tagalog, he or she can pick up the unique acoustic properties of those languages, too. By age three, a toddler can converse with a parent, a playmate or a stranger. This is a preview.